Hydraulic drive for machine tools



HYDRAULIC DRIVE FOR MACHINE TOOLS Filed Sept. 14 1929 3 Sheets-Sheet 1 IN VEN TOR.

0 WAL ER FE'HE'IS.

, ATTORNEY.

May 14, 1935. w. FERR|$ HYDRAULIC DRIVE FOR MACHINE TOOLS Filed Sept. 14, 1929 5 Sheets-Sheet 2 INVENTOR. WAL TEE FERE'IS'.

ATTORNEY.

May 14, 1935. w. FERRIS 2,001,059

HYDRAULIC DRIVE FOR MACHINE TOOLS Filed Sept. 14, 1929 3 Sheets-Sheet 5 INVENTOR. WA LTER FEHHJS.

A TTORNEY. 4

Patented May 14, 1935 PATENT OFFICE nrmmumc nnrvn Foa moms TOOLS Walter Ferris, Milwaukee, Wis, assignor to The oilgear Company, Milwaukee, Wis, a corporation of Wisconsin Application September 14, 1929; Serial No. 392,507

12 Claims.

This invention relates to hydraulic drives for machine tools of the continuously reciprocating .type such as planers, shapers and the like.

One object of the present invention is the provision of improved means for automatically reversing and changing the rate of movement of the reciprocating part at the end of each stroke.

Another objecitis the provision of improved means for effecting an intermittent cross-feed between the tool and work.

Another object is the provision in a hydraulically driven machine of the character mentioned of means energized from the hydraulic drive system for varying the relation between the tool and work to gauge the depth of cut.

Other more specific objects and advantages will appear from the following description of a shaper equipped with a hydraulic drive system embodying the present invention.

In the accompanying drawings:-

Figure 1 is a front elevation of a shaper equipped with a hydraulic drive embodying the present invention.

Fig. 2 is a side elevation looking from left to right in Fig. 1.

Fig. 3 is a diagrammatic view of the hydrauliccircuit employed.

Fig. 4 is a. diagrammatic view of a portion of the hydraulic circuit illustrating other characteristic positions of the pilot valve, reversing valve, and by-pass valve employed therein.

, Fig. 5 is a sectional view of the by-pass valve illustrating a third characteristic position there- Fig. 6 is a sectional view of the pump regulating valve illustrating a second characteristic position thereof.

Figs. 7, 8 and 9 are sectional views of table con-- trol valve illustrating three additional positions thereof.

Fig." 10 is a sectional view of the cross-feed cylinder showing the same in a second characteristic position.-

For purposes of illustration and explanation the hydraulic drive of the present invention is shown applied to a shaper of a well known type. The shaper conventionally illustrated in Figs. 1 and 2 comprises a main frame I having horizcntaLways II for supporting and guiding a, tool carriage 12. The carriage I2 is in this instance hydraulically reciprccated by a piston I3 working in a cylinder l4 fixed within the frame H), the piston I3 being connected through rods 15 to lugs l6 formed integral with and depending from the carriage (see Fig. 3). The work support is in the form of a table I! grooved to receive a horizontal cross-rail l8 upon which it is supported and guided for travel transversely of the direction of reciprocation of the carriage. The rail I8 is formed as an integral part of a vertically adjustable block l9, guided by verticalways 20 on the front face of the frame l0, and releasably locked at any desired elevation by a wedge 2| which is seated'within a vertically tapered recess 22 within the block l9 and bears against the ways 20. In this instance the wedge 2| is actuated to lock and release the table supporting block l3 by a piston 22' closely fitted within a bore 23 within the block l9, and the block .l3 is hydraulically elevated by a hollow plunger 24 telescopically arranged within an upright cylinder 25 on the base. 26 of the machine frame 13. W

As indicated in Fig. 3, the lower end 21 of the plunger 24 is closed and a pipe 28 anchored in the base 26 projects upwardly therethrough. A passage 23 leading from the lower end of bore 23 communicates with pipe 28 through the plunger 24. A pipe,33 communicating with the upper end of bore 23, a pipe 3| communicating with pipe 28, and a pipe 32 communicating with the cylinder 25 are 'all placed under the control of a valve preferably such as will now be described. Thisvalve comprises a cylindrical housing 33 having a I longitudinal bore the opposite ends of which communicate with each other through a pipe 34 which is connected with an exhaust pipe 35. The bore contains four, annular grooves 35, 36, 31, and 38. Groove 35' communicates with pipe 30; groove 36 communicates with a pressure pipe 39, which 35 leads from an appropriate pressure source to be later described; groove 31 communicates with pipe 3|; and groove 38 communicates with pipe 32. A plunger is closely fitted for reciprocation within the bore. This plunger has three heads 40 40, 4|, and 42 closely fitted within the bore. The relatively narrow head 40 controls the groove 35', the relatively narrow head 4| controls the grooves 31 and 38, and the elongated head 42 serves to cover the groove 38 in some positions of the valve.

A- longitudinal passage 43 through the valve plunger communicates through ports 44 with the reduced portion of the plunger between the heads 4| and 42. The valve is operated by a stem 45 attached to one end of the valve plunger and equipped with an appropriate handle 46.

The arrangement is such that with the plunger, of valve 33 in the leftextreme position of Fig. 3, pipe 32 is blocked by head 42; pipe 3| is open to exhaust through groove 31, ports 44, and passage 43; and pipe 39 is open to the pressure pipe 39 so that the upper end of bore 23 is exposed to pressure and the block I9 is locked by the wedge 2|. When the plunger of valve 33 is shifted into the position illustrated in Fig. '7, pipe 30 is open, exhaust pipe 32 is still blocked, and pipe 3| is opened to the pressure pipe 39 so that the lower end of bore 23 is exposed to pressure to thereby lift the piston 22 and wedge 2| to release the block l9. The block I9 and table H are then supported by the stationary column of liquid within the cylinder 25. When the plunger of valve 33 is shifted into the position shown in Fig. 8, pipe 30 remains open to exhaust, pipe 3| remains connected with pressure pipe 39, and pipe 32 isopened to the exhaust through ports 44 and passage 43 to thereby permit the block I 9 and table H to lower. When the plunger of valve 33 is shifted into the extreme right position of Fig. 9, pipe 3|) remains open to the exhaust, pipe 3| remains open to pressure pipe 39, and pipe 32 is also opened to the pressure pipe to thereby elevate the plunger 24, block l9 and table |1. After shifting this valve into the position of Figs. 8 or 9 to thereby lower or elevate the table into proper position this valve is ordinarily returned into the left extreme position of Fig. 3 so as to pull the wedge 2| downwardly and securely lock the block |9 against further movement. A hydraulic system has thus been devised for effecting a ready adjustment of the work support in accordance with the requirements of the work.

The table I1 is fed along the rail |8 by a horizontal screw 41 threaded through a boss 48 on the table and journaled at its opposite ends in the opposite ends of the block l9. This screw 41 is-actuated by a ratchet wheel 49 fixed thereto andintermittently rotated in a well known manner by a pawl 50 carried by a rock arm 5|. In this instance the arm 5| is actuated by a link 52 connected to a crank pin 53 adjustably fixed in a diametrically disposed slot 54 formed on the face of a crank' disk 55. The stroke of the arm 5| may thus be varied by adjustment of the pin 53 toward or from the axis of the disk 55 to thereby regulate the rate of cross-feed of the table H. The disk is hydraulically oscillated in a manner to be later described by a plunger 56 fitted within a cylinder 51 and connected to the disk through appropriate linkage 56'. The bore of the cylinder 51 contains two annular grooves 58 and 59 so positioned as to be alternately uncovered by the plunger at the completion of successive strokes thereof. Groove 58 is connected to a pipe 60, leading from the right end of cylinder 51, through a pipe 6| containing a check valve 62. Check valve 62 prevents flow of liquid through pipe 6| from pipe 68. Similarly groove 59 is connected through a pipe 63 with a pipe 64 leading from the left end of cylinder 51, a check valve 65 preventing flow through pipe 63 from pipe 64.

It will be noted from an inspection of Fig. 3 that pipe 64 leads to the left end of cylinder l4, and that pipe 68 leads to a reversing valve 66 of a type to be later described. A pipe 61 leadingv from the right end of cylinder l4 also connects with the reversing valve 66. Cylinder 51 is thus connected in series with the cylinder |4 through this valve. For a purpose which will later appear the pipe 60 contains a spring-loaded valve 68 which offers a predetermined resistance to the flow of liquid through pipe 68 to the cylinder 51. A check valve 69 connected across the valve 68 permits a free flow of liquid through pipe 60 from the cylinder 51.

passage 19 in the block. A passage in the block intercepts the bore and is connected through a pipe 8| with an annular groove 82 controlled by the head 13. Pipes 83 and 84 leading to the opposite ends of the bore serve as pressure supply pipes through which the plunger is hydraulically actuated.

Passages 19 and 89 communicate with the bore of a by-pass valve 85 which is also contained within the block 15. The bore of this valve contains a relatively wide annular channel 86 which communicates with passage 88 and with an exhaust pipe 81; an annular groove 88 which communicates with a supply pipe 89 which connects with supply pipe 39 leading to valve 33; an annular groove 90 which communicates with the passage 19; an annular groove 9| which communicates with a drain pipe 92; and an enlarged end chamber 93 which also communicates with the drain pipe 92. A plunger 34 having an intermediate reduced portion 95 is fitted within the bore and is manually actuated and controlled by a stem 96 having an appropriate handle 91. That end of the plunger within the chamber 93 is bored out to receive a spring loaded relief valve 98 which controls a duct 99 having communication with a transverse duct H19 in the plunger.

Ports |9| in the plunger permit liquid to escape into the chamber 93 and thence into the drain pipe 92. The relief valve is set to open at a moderate pressure of about 509 pounds. per square inch and functions only during vertical adjustment of the table supporting block |9 to limit the operating pressure in the circuit at that time. Thus when the plunger 94 is in the left extreme position of Fig; 5 supply pipe 89 is blocked, except for its connection with the ducts I00 and 99 leading to the relief valve 98, and except for its connection with the pipe 39; so that all of the liquid supplied through pipe 89 is available, at a pressure limited by valve 98, to operate the table lifting plunger 24 and the looking wedge 2|. When the plunger 94 is shifted into the intermediate or neutral position of Fig. 3 the supply pipe 89 is connected to the exhaust pipe 81 to thereby destroy the pressure in pipe 89 and thus render the entire system inactive. When the plunger 94 is shifted into the right extreme position of Fig. 4 supply pipe 89 is disconnected from the exhaust pipe 81 and connected with the passage 19 so that the liquid supplied through pipe 89 is then available to move piston I3 in a direction determined by the position of the reversing valve 66.

Referring again to the reversing valve 66 it aooipso $9 to the reversing valve 66, and then through channel Tl, groove 82, pipe 8|, passage 80, and channel 86 to the exhaust pipe 81. Then when the plunger of the reversing valve 66 is shifted into the left extreme position of Fig. 4, passage "i9 is connected with pipe 60 and liquid from the supply pipe 89 is directed through pipe tt and the resistance valve 68 to the right end of cylinder 5?, forcing the-piston 56 toward the left until groove 59 is uncovered as indicated in Fig. 10, then through pipes 63 and M to the left end of cylinder it to thereby drive the piston lit and tool carriage l2 toward the right on a return or idle stroke. During this return stroke liquid discharged from the right end of cylinder it passes through pipe Bl to the reversing valve and then through passage 80 and channel t6 to the exhaust pipe M. Then when the plungerof the reversing valve 66 is returned to the right extreme position of Fig. 3 driving liquid is again supplied through pipe tl to the right end of cylinder M to again advance the tool carriage. lt on a cutting stroke, and the liquid discharged from the left end of cylinder it through pipe (it enters the left end of cylinder tl so as to return the piston 56 into the right extreme position of Fig. 3 to thereby uncover groove tt and permit the liquid to pass through pipes ti and tt through the reversing valve and to the exhaust pipe 8T.

It will thus be noted that the piston tt is thus hydraulically actuated upon each shifting of the reversing valve t6 and upon each reversal of mo-- tion of the piston it and tool carriage lt. Thus as the piston l3 reverses at the end of a cutting stroke the piston 56 is promptly shifted in such direction as to rotate the crank disk 55 clockwise (Fig. 2) to thereby cause the arm El and pawl 50 to execute an idle stroke; and asthe piston it reverses at the end of a return stroke the piston 56 is promptly shifted in the opposite direction to thereby swing the arm tl clockwise (Fig. 2) and thus impart a predetermined rotation to the feed screw 41. The work table it is thus advanced a predetermined distance across the line of cut at the beginning of each cutting stroke of the tool carriage it but prior to actual engagement of the tool with the work. The fact that the cylinder 51! is connected in series with cylinder it in the manner hereinabove described insures the completion of each feed movement of the table during a predetermined advance of the tool carriage on its cutting stroke.

In the machine shown the reversing valve tt is automatically actuated by means now to be described under the control of the tool carriage it. This means includes a pilot valve ltt of a well known type including a plunger having two end heads N33 and Hit connected by a reduced portion ltt and closely fitted for reciprocation within a bore. The opposite ends of the bore are connected to a drain pipe Hit. A supply pipe ltli com- .municates at all times with that space surrounding the reduced portion ltt of the plunger. Pipe.

83 leading from the left end of the reversing valve 66 connects with the pilot valve at such point as to be controlled by head ltt, and pipe tt leading from the right end of the valve tt connects with the pilot valve at such point as to be controlled by head lt l. The arrangement is such that when the plunger of the pilot valve W2 is in the left extreme position of Fig. 3,.pipe 83 is open to supply pipe MIT, and pipe 84 is open to the drain pipe I06, so that the plunger of the reversing valve 8 is shifted into and retained in the right extreme position of Fig. 3; and when the plunger of the pilot valve is shifted into the right extreme position of Fig. 4 pipe 84 is opened to the supply pipe lt'l, and pipe t3 is opened to the drain pipe 806, so that the plunger of the reversing valve is then shifted into the left extreme position of Fig. l.

The pilot valve W2 is operated and controlled by a stem ltt having a pin and slot connection with a lever ltt rockably supported upon a pivot pin llt fixed in an appropriate bracket lll projecting from the rear of the machine frame It. The upper end lit of the lever projects into the path of travel of a pair of trip dogs lit and lit of a well known type adjustably fixed on a tail rod l it carried by and extending rearwardly from the tool carriage lt. The trip dogs are so arranged that as the tool carriage l2 approaches the end of its cutting stroke dog lit strikes the end ll? of the lever ltt to thereby shift the pilot valve into the right extreme position of Fig. 4, and as the tool carriage it approaches the end of its return stroke dog llt strikes the end N2 of the lever to shift the pilot valve into the left extreme position of Fig. 3.

The hydraulic system is supplied with liquid under pressure from a constant speed variable, displacement pump llt of a well known type. The pump shown is substantially identical with that described in my prior Patent No. 1,558,002, issued October 20, 1925. 'It is driven at constant speed by appropriate means such as a pulley l l1! and delivers liquid through the pipe lit at a rate depending upon the position of .an arm llt rockably supported at its lower end upon a shaft M9 fixed in the housing ltt. The pump receives liquid through the pipe t'l. A high pressure relief valve ltl connected with the pipe t9 protects the pump and hydraulic circuit against excessive pressures and'discharges into the drain pipe. Hit. A gear pump ltt of a well known type draws liquid from the bottom of the pump housing and discharges into the pipe ltl leading to the pilot valve ltt. The'pressure created by the gear pump ltt is limited by a low pressure relief valve ltt connected into a pipe lZt which is connected at one ofits ends to the pipe lt'l and discharges into the pump housing it. A pipe l25 connects the pipe ltl with the return pipe tl so that pipe til is maintained flooded with liquid at gear pump pressure, and a check valve lzt within the pipe ltt prevents the escape of liquid through pipe I25 whenever the pressure in pipe tl exceeds gear pump pressure.

In this instance novel means are provided for regulating the displacement of pump lit to thereby regulate the rate of flow of liquid in what was heretofore referred to as the supply pipe tt. Referring to Fig. 3 this means includes a rod lt'l guided for lengthwise movement in the upper portion of the pump housing and carrying a cross-pin ltt engaged within a fork ltt on the upper end of the rock arm llt. A compression spring ltt bearing against the inside of the pump housing and against a collar ltl on the rod ltl urges the rod and arm lit toward the right to reduce pump displacement. A wedge bar ltt, guided for lengthwise adjustment in an appropriate bracket ltt, extends through a slotted head ltt carried by one end of the rod ltl so as to limit the movement thereof toward the right. With the parts in the positions shown in Fig. 3 the pump is delivering at a relatively slow rate through the pipe til. This is the condition assumed during the cutting stroke of the tool carriage I2, and by adjusting the wedge bar I32 up or down this rate may be decreased or increased to thereby decrease or increase the cutting speed of the tool. A hand lever I35 on the bracket I33 and engaged with the wedge bar I32 provides a convenient means for adjusting the same. The rod I21 also carries a piston I38 at the other end thereof which works in a cylinder I31 and by which the rod I21 is shifted toward the left against the pressure of the spring I30 to thereby effect a substantial increase in pump displacement with a corresponding increase in the rate of flow through pipe 89 so as to effect a rapid movement of the tool carriage I2 during the return stroke thereof. The piston I38 is energized by gear pump pressure under the control of an appropriate automatic valve I38 such'for instance as will now be described.

The valve I38 is shown in Figs. 3 and 6 and is provided with a casing having a longitudinal bore which terminates in an enlarged chamber I39 at one end thereof. Chamber I39 is connected through a pipe I40 with the pipe 81 leading to the right end of cylinder I4. The opposite end of the bore is connected through a pipe I with pipe 80 at a point between the resistance valve 88 and the reversing valve 88. The bore contains five annular grooves I42, I43, I44, I and I48. One end groove I42 is connected with a drain pipe I41 through a chamber I48 and the other end groove. I48 is connected to the same drain pipe through a passage I49. Groove I43 communicates with the left end of cylinder I31 and groove I45 with the rear end of the cylinder I31. The middle groove I44 communicates with supply pipe I01 through a pipe I50. The bore contains a five headed plunger I5I having a sliding fit therein and containing a bleed duct I52 extending longitudinally therethrough to thereby provide a restricted passage between the end chamber I39 and the other end of the bore. A compression spring I53 withinthe end chamber I39 yieldably retains the valve plunger I5I in the left extreme position of Fig. 3, in which position the right end of cylinder I31 is open to the drain passage I49 and the left end thereof is exposed to the pressure in supply pipe I01, so that the piston I38 is urged toward the right to assist the spring I30 in retaining the rod I31 in the position of Fig. 3. Such is the position normally assumed by the valve plunger I 5| during. the cutting stroke of the tool carriage I2 and also when the machine is at rest. When the plunger of the reversin valve 88 is shifted into the position of Fig. 4 so as to connect the supply pipe 89 with the pipe and thus start the tool carriage rearwardly on a return stroke, the pressure in pipe 80 is transmitted through pipe I4I to thereby shift the valve plunger I.5I into the right extreme position of Fig. 6, to thereby open the right end of cylinder I31 to the supply pipe I01 and thus shift the rod I21 to the left to increase pump displacement.

A brief description of the operation of the machine will now be given assuming that the several parts are in the positions indicated in Fig. 3 and that the pump H8 is running, but since the by-pass valve is in neutral position in this figure pipe 89 communicates with pipe. 81 so that the pump is by-passed and the' machine is at rest. If before starting the machine it is desired to raise or lower the work table I1 to accommodate a new piece of work, the plungerpf the by-pass valve 85 is first shifted into the left extreme position of Fig. 5 so that the end of supply pipe 89 is blocked except through the relief valve 98. This immediately raises the pressure in pipes 89 and 39 up to the limit established by the relief valve 98. Then to elevate the table the plunger of valve 33 is shifted into the right extreme position of Fig. 9 so that the bottom of the bore 23 is exposed to the pressure in pipe 39 through pipe 3I to thereby release the wedge 2| and the cylinder 25 is exposed to the pressure in pipe 39 through pipe 32 to elevate the block I9 and table. Or to lower the table the plunger of valve 33 is shifted into the position of Fig. 8 so that the bottom of the bore 23 is again exposed to pressure to release the wedge 2I and the cylinder 25 is opened to the exhaust pipe 35 to permit the table to lower by gravity. When the I force the wedge 2I downwardly to lock the tablesupporting block I9. The plunger of the bypass valve 85 is then returned into the position of Fig. 3.

When it is desired to adjust the table to a definite position above the position in which it was last set, the table is first elevated to a position above the desired ultimate position by shifting the valve 33 into the right extreme position of Fig. 9. The valve 33 is then shifted into the position of Fig. 8 to again lower the table until the desired elevation-is reached, whereupon the valve 33 is again shifted into the position of Fig. 3 to lock the table in that position in the manner above described.

To start the machine the plunger of the bypass valve 85 is shifted into the right extreme position of Fig. 4 to thereby connect the supply pipe 89 with the passage 19 leading to the reversing valve 88. With the reversing valve in the position shown in Fig. 3, liquid passes from the passage 19 through the pipe 81 to the right end of the cylinder I4 to thereby drive the piston I3 and tool carriage I2 toward the left on a cutting stroke. The pressure in pipe 81, transmitted through pipe I40 to the chamber I39 holds the plunger of the pump regulating valve I38 in the position of Fig. 3'so that the pump H8 is then delivering at a relatively slow rate through pipe 89 and the cutting stroke is executed at a relatively slow speed.

The cutting stroke continues until the trip dog II4 strikes the lever I09 and the plunger of the reversing valve 88 is shifted to the left into the position of Fig. 4 and the passage 19 is thereby connected to pipe 80. Liquid supplied from pipe 89 through passage 19 then flows through pipes 80 and I H to the left end of the pump valve I38 to thereby shift the same into the right extreme position of Fig. 6, so that the rod I21 is shifted toward. the left to thereby increase pump displacement and thus increase the rate of flow through pipe 89. Afterthus shifting the plunger of valve I38 to the right extreme position the pressure in pipe 80 immediately rises sufiiciently to open the valve 88 and enter the right end of cylinder 51. Piston 58 then shifts to the left, as previously described, and the liquid from pipe 80 passes on through check valve 85 and pipes 83 and 84 to the left end of cylinder I4 to drive the piston I3 and tool carriage I2 toward the right on a return stroke. Since pump displacement has been increased simultaneously with this reversal of carriage movement the return stroke is executed at an increased rate.

The return stroke continues until the trip dog H3 strikes the lever I09 and shifts the plunger of the pilot valve W2 into the left extreme. position of Fig. 3, to thereby return the plunger of the reversing valve 86 into the right extreme position of Fig. 3 and thus again connect passage HQ with the pipe 61! and passage 80 with pipe 6| Driving liquid then passes from pipe 89 through pipe 61 to the right end of the cylinder M to drive the piston l3 and carriage it, toward the left on the next cutting stroke; and the piston 56 is again actuated by the liquid passing from the left end of the cylinder M through pipe 64 so as to rotate the feed screw M and thereby shift the work table ll transversely of the path of the tool prior to engagement of the tool with the work in the manner previously described. Simultaneously the pressure in pipe t'i is transmitted through pipe Mil to thereby return the plunger of the pump valve 1138 into the position of Fig. 3 and thus again reduce pump displacement.

The reciprocation of the carriage l2 thus continues with a relatively slow movement during the cutting strokes and a relatively fast movement during the return strokes, and with an intermittent transverse advance ofthe table il at the beginning of each cutting stroke, until the ma-- chine is again brought to rest by returning the plunger ti t of the by-pass valve into the'intermediate position of Fig. 3. Whenever the machine is stopped the plunger of the pump valve I138 assumes the position shown in Fig. 3, since even though the same may have been in the position shown in Fig. 6 when the machine was stopped, the bleed duct l 52 in the plunger permits liquid to escape therethrough from the left end of the valve bore as the valve plunger is urged toward the right by the spring I53.

Various changes may be made in the embodiment of 'the inventionhereinabove specifically described without departing from or sacrificing the advantages of the invention as defined in the appended claims.

I claim:-

1. In a shaper or the likethe combination of a reciprocating tool carrier, a work holder, an adjustable support upon which said holder is mounted for travel transversely of the direction of motion of said tool carrier, hydraulically actuated means for driving said carrier and said holder, hydraulically actuated means for adjusting said support, a pump fed hydraulic circuit for driving said first and last named hydraulically actuated means, and a single valve alternatively operable to render said first or last named hydraulically actuated means active selectively.

2. In a shaper or the like the combination of a reciprocating member, hydraulically actuated means for driving said member, a second member adjustable relative to the path of travel of said reciprocating member, a second hydraulically actuated means for adjusting said second member, a hydraulic circuit for driving both of said means, a valve adjustable to render either of said means active to the exclusion of the other, and a relief valve rendered effective by said valve to limit the pressure in said circuit when said second hydraulically actuated means is rendered active.

3. The combination, with a machine having a reciprocable carriage, of a hydraulic motor for reciprocating said carriage, a variable displacement pump, means including a reversing valve for directing liquid from said pump to said motor reversing valve for directing liquid from said 10 pump to opposite ends of said motor alternately to cause it to drive said carriage in opposite directions alternately, and means actuated by liquid from said pump and connected between said pump and said motor in parallel with said motor 15 for varying pump displacement at each end of the stroke of said motor.

5. The combination, with a machine having a reciprocable carriage, of a hydraulic motor for reciprocating said carriage, a variable displace- 20 ment pump, means including a reversing valve for directing liquid from said pump to said motor to cause it to drive said carriage in opposite directions alternately, a fiuid motor for varying the displacement of said pump, an auxiliary 25 pump, means including acontrol valve for directing liquid from said auxiliary pump to said fluid motor to operate the same, and fluid actuated means connected in parallel with said hydraulic motor for operating said control valve.

6. The combination, with a machine having a reciprocable carriage, of a double acting hydraulic motor for reciprocating said carriage, a variable displacement pump, means including a reversing valve for directing liquid from said pump to op- 35 posite ends of said motor alternately to cause it to drive said carriage in opposite directions alternately, a fluid motor for varying the displacement of said pump, an auxiliary pump, means including a control valve for directing liquid from said auxiliary pump to said fluid motor to operate the same, and fluid actuated means connected in parallel with said hydraulic motor for operating said control valve each time said hydraulic motor is operated in either direction to thereby vary pump delivery in accordance with the direction of motor actuation.

'7. The combination, with a machine having two relatively movable supports, of a hydraulic driving motor connected to one of said supports for reciprocating the same, a variable displacement pump, means including a reversing valve for directing liquid from said pump to said motor to cause it to drive said support in opposite directions alternately, means actuated by liquid from 5.:

said pump and connected between said pump and said motor in parallel with said motor for varying pump displacement, and a hydraulic cross feed motor mechanically connected to one of said supports for moving it relative to the other support 6( and hydraulically connected in series with said driving motor to be actuated in one direction by liquid delivered to said motor and in the opposite direction by liquid exhausted from said motor.

8. The combination, with a machine having a 6.

reciprocable carriage, of a hydraulic motor for reciprocating said carriage, a variable delivery pump, means including a hydraulically operated reversing valve for directing liquid to said motor to cause it to drive said carriage in opposite 7 directions alternately, means actuated by liquid from'said pump and connected between said pump and, said motor in parallel with said motor for varying pump displacement, means for delivering liquid to said hydraulically operated 7 valve to operate the same including a pilot valve, and means for shifting said pilot valve at each end of the path of said carriage.

9. The combination, with a machine having a reciprocable carriage, of a hydraulic motor for reciprocating said carriage, a variable delivery pump, means including a hydraulically operated reversing valve for directing liquid to said motor to cause it to drive said carriage in opposite directions alternately, means actuated by liquid from said pump and connected between said pump and said motor in parallel with said motor for varying pump displacement, an auxiliary pump for supplying liquid to said hydraulically operated valve to operate the same, a pilot valve for controlling the delivery of operating liquid to said hydraulically operated valve, and means operable at each end of the path of said carriage for shifting said pilot valve to thereby cause continuous reciprocation of said carriage.

10. The combination, with a machine tool having an adjustable support, of a fluid motor for adjusting said support, means for clamping said support in adjusted positions, a fluid motor for operating said clamping means, a source of motive fluid, and fluid channels connecting said source to both of saidmotors and including a multiposition valve, said valve having ports and passages alternatively connectable to direct fluid from said source to either end of said clamping.

motor orto said support motor selectively.

11. The combination, with a machine tool having an adjustable support, of a fluid motor for adjusting said support, means for clamping said support in adjusted positions, a fluid motor for operating said clamping means, a source of motive fluid, and fluid channels connecting said source to both of said motors and including a multiposition valve, said valve having ports and passages alternatively connectable to direct fluid from said source to either end of said clamping motor or to said support motor selectively or simultaneously to said support motor and to one end of said clamping motor.

12. The combination, with a machine tool having a carriage reciprocable in a horizontal plane and a vertically adjustable support, of means for clamping said support in adjusted positions, a

double acting fluid motor for operating said clamping means, a single acting fluid motor for elevating said support, a source of motive fluid, and fluid channels connecting said source to both of said motors and including a multi-position valve, said valve having ports and passages alternatively connectable to selectively. connect either end of said clamping motor or one end of said support motor to said source or the other end of said support motor to a drain.

WALTER FERRIs. 

